1. Field of the Invention
This invention relates to a reflector and, more particularly, to an orientation dependent reflector for use in reflecting light to facilitate the determination of angular orientation of an object.
2. Description of the Background Art
Presently, many types of reflectors are available and in use today throughout the industry. However, many of the prior art reflectors do not provide for the sensing of the orientation of an object in multiple dimensions. The majority of the prior art reflectors used to serve the measuring of orientation are limited to facilitating measurement in a single dimension. Of those prior art reflectors used today in the industry for determining orientation in more than one dimension, a light detector that utilizes two-dimensional image processing or a group of sensors arranged in a line or over an area is required. Light detectors capable of two-dimensional image processing are quite expensive and not practical for all commercial applications.
Most importantly, the prior art reflectors available today in the industry lack the ability to gather light in adequate amounts so to facilitate being instantaneously detected from a remote position. Due to the prior art reflectors having an inherent inadequate ability to gather light, many of the prior art reflectors used for orientation purposes are resultingly large in size rendering them bulky and cumbersome to attach and utilize. Representative of various prior art reflectors used in orientation determination can be seen as utilized in U.S. Pat. Nos. 3,194,563; 3,697,183; 4,155,555; 4,251,077 and 4,341,384, the disclosures of which are hereby incorporated by reference herein.
While the reflectors disclosed in the abovereferenced prior art patents, used for orientation purposes, serve to provide reflections of light in varying forms for detecting orientation, it can be seen that many require light detectors capable of two-dimensional image processing or, alternatively, require a group of sensors arranged in a line or over an area. Many of the reflectors are large in construction rendering them bulky and cumbersome to use, many are incapable of gathering adequate amounts of light to facilitate a light detector determining the centroid of reflection on the reflector, and many are expensive and complex to manufacture.
Other, less relevant, forms of reflectors can be seen as used in systems for measuring an aspect of movement of an object in U.S. Pat. Nos. 3,895,366; 4,136,387; 4,137,566; 4,146,230; 4,254,956; 4,304,406; 4,488,173; 4,583,862; 4,910,410; 5,187,540; 5,257,084; 5,319,577; 5,353,358; and 5,453,686, the disclosures of which are hereby incorporated by reference herein.
Of the prior art reflectors utilized in the above-referenced disclosures, the most relevant is disclosed in U.S. Pat. No. 3,697,183, issued to Knight. The Knight patent discloses the use of two gratings for which light passes through to a specular reflector whereupon reflection is produced. However, the specular reflector utilized in Knight still exhibits the inadequate capability of gathering adequate amounts of light for being detected from a remote position. Further, due to the light gathering properties of the reflector utilized in Knight, only measurements of small and relatively slow changes in orientation are provided for. Further, Knight requires a group of sensors arranged in a line to accomplish the detection.